For the great size and magnitude of the beasts that walked our earth hundreds of millions of years ago, relatively little is known about their existence. Over a century’s worth of fossil discoveries seem to have only scratched the surface. While recent sauropod discoveries have shed new light on some issues, there is still much to learn about the age of the dinosaurs.
Sauropoda is a suborder of the order saurischian, and includes the largest dinosaurs known to man. They feature very long necks with small heads and long tails, and are believed to have been herbivores.
Out of the myriad of identified dinosaurs, one of the most familiar is the Brontosaurus. The mention of this reptile’s name is sure to conjure up images of a sauropod for dinophiles of all ages.
Sauropods, “lizard foot” in Latin, were large, four-legged behemoths that are best known for their colossal sizes and their extra long necks – most being longer than a giraffe’s – the tallest living animal today at 14 feet tall.
Based on sauropod fossils, including their teeth, stomach contents and feces, we know that probably all of them were herbivores. Stones called gastroliths can be found in the stomachs of sauropods, indicating that they swallowed them to grind the vegetation they ate – the skulls of sauropods showed that they did not have flexible cheeks to support chewing.
Most sauropods lived during the Jurassic Period (201 million to 145 million years ago), considered to be the golden age of dinosaurs with the massive collection of fossils found from rocks pre-dating that era.
Several other well-known sauropods include Brachiosaurus, Diplodocus and Argentinosaurus – the latter of which is believed to have grown to about 40 meters long, much larger than even the blue whale.
Brontosaurus or Apatosaurus?
However, as widely recognized as Brontosaurus is, it was once the subject of a paleontological debate that went on for more than a century.
The first known fossil records of Brontosaurus came during the late 1800s, during what is known as the Bone Wars or the Great Dinosaur Rush.
After remains of a sauropod were found in Colorado, paleontologist Othniel Charles Marsh named the dinosaur Apatosaurus ajax. Two years later, another more complete and larger fossil was found in Wyoming, which Marsh named Brontosaurus excelsus, or “noble thunder lizard.”
In 1903, paleontologist Elmer Riggs – the man who named the sauropod Brachiosaurus – claimed that there were too many similarities between the Apatosaurus and Brontosaurus fossils for both to exist as separate genus, let alone species.
Thus, since Apatosaurus was named first, it was adopted to identify both what had been known as Brontosaurus and Apatosaurus under one genus. For the next century, the name Brontosaurus would fade from the palaeontological records, though it would be used in other forms of media.
That is… until 2015, when a group of paleontologists came together to study more recent sauropod fossils and made a substantial discovery, reported by Charles Choi for Scientific American.
Upon examining 81 specimens from around the world and 477 anatomical traits, the group may have enough evidence to show that Brontosaurus and Apatosaurus were two different dinosaurs, after all. Brontosaurus appeared to have a more massive build with a lower and thicker neck than the Apatosaurus, giving the scientists justification to differentiate the two.
According to Professor Paul Barrett of the Natural History Museum in London, the skeletons of Apatosaurus and Brontosaurus were indeed similar to each other, yet exhibited differences in the neck, back, and shoulder bones.
“These differences are only clear when you’re able to examine a large number of different skeletons to see how these features vary from animal to animal,” Paul said.
While the research is still debated to this day, those who long for the official return of the Brontosaurus may rejoice at the possibility of it being immortalized in the museum, just as it has been in pop culture.
A respiration disaster
In other sauropod news, paleontologists have made another discovery regarding a dinosaur’s breathing problems.
Dr. Cary Woodruff, director of paleontology at the Great Plains Dinosaur Museum in Malta, Montana, was examining the bones of a dinosaur named Dolly, a fossilized diplodocid sauropod unearthed more than 30 years ago. Woodruff discovered what looked like “broccoli-like growths” in some of Dolly’s neck bones, particularly parts of the neck that would have been connected to air sacs of the dinosaur’s respiratory system.
Baffled by the discovery, he went to social media for clues, where he quickly received an answer from several fellow scientists. According to them, the unusual growths resembled that of protrusions found in modern birds that damage their respiratory system.
These protrusions are the result of an infection called aspergillosis, caused when birds breathe in mold spores, as researchers wrote in Scientific Reports. Aspergillosis is deadly to birds if not treated.
Since scientists believe that birds are descended from dinosaurs, they naturally made the link to assume that something similar happened. Either way, no one knows whether Dolly died directly from the infection, or if the infection made her vulnerable to predators.
“We know so little about the diseases dinosaurs suffered, unless those maladies were somehow able to leave marks on fossil bone,” Steve Brusatte, professor of paleontology and evolution at the University of Edinburgh, said.
In early February, in Catalonia, Spain, scientists in Spain unearthed a species of titanosaur – generally considered the largest group of all the sauropods.
Named Abditosaurus kuehnei, “forgotten lizard,” this sauropod is said to have lived in the late Cretaceous Period (145 million to 65 million years ago). The creature, however, is estimated to be a mere 17.5 meters long and weighed around 14,000 kilograms.
Despite the beliefs that titanosaurs were colossal compared to most other sauropods, titanosaurs in the Cretaceous were usually smaller, helping them adapt to the changing world of the Cretaceous – long after the golden age of sauropods had passed and almost at the tail-end of the Age of Dinosaurs, Spanish paleontologist Dr. Bernat Vila said.
“The species that evolved there tend to be relatively small, or even dwarves compared to their relatives living in large landmasses, due primarily to the limitation of food resources in islands.”
The fossil found is also the most complete fossil of a titanosaur ever found. Museum director Dr. Angel Galobart considered it “lucky” to have found such a complete fossil in the Pyrenees, since the location has a “troubled geologic history.”
It is believed that Abditosaurus could have come from Createcous South America, like most of its other titanosaur brethren, and crossed into what is now Europe via a drop in sea levels.
“During the Jurassic and Cretaceous, Iberia was the point of connection between Eurasia, Africa and North America,” paleontologist Dr. Miguel Moreno said. “Studying how Abditosaurus kuehnei relates to the fauna of these continents helps us to understand when there were connections between them, and when they became isolated.”